Add pathfinding

[mathiasbynens]

@TibiaTracker has worked on this and will submit a patch soon: https://twitter.com/TibiaTracker/status/744754176853344257

[tibiacentral]

Working on improvements to this and will be ready soon.

It will have the option to support ladders and teleports.

[mathiasbynens]

Sounds amazing, @tibiacentral! 👍